# CathSource vs Differential Diagnosis Guide

The clearest difference is review sentiment: Differential Diagnosis Guide at 89% against CathSource's 43%. Differential Diagnosis Guide also leads on rating (4.5 vs 1.6) and monetization model (free vs paid). On price, ratings volume, update cadence and ads there is nothing between them.

Both are free to download. Neither carries in-app purchases, so what you see is what you pay.

Differential Diagnosis Guide holds the better App Store score, 4.5 against 1.6. Both are backed by a comparable volume of ratings — 23 and 22 respectively. Written reviews point the same way: 43% of CathSource's written reviews are positive against 89% of Differential Diagnosis Guide's.

CathSource ships an update every 2 months, Differential Diagnosis Guide every 4 months. The most recent releases landed on September 18, 2026 and June 4, 2026 respectively.

## The numbers

| Metric | CathSource | Differential Diagnosis Guide |
| --- | --- | --- |
| Price | Free | Free |
| Rating | [1.6 (23 ratings)](https://appshunter.io/ios/app/cathsource/id420847275/reviews) | **[4.5 (22 ratings)](https://appshunter.io/ios/app/differential-diagnosis-guide/id523946690/reviews)** |
| Number of ratings | **23** | 22 |
| Positive reviews | 42.9% of reviews | **88.9% of reviews** |
| In-app purchases | No | No |
| Ads | No | No |
| Update frequency | **Every 2 months** | Every 4 months |
| Monetization | Paid | **Free** |
| Size | 79 MB | 48 MB |
| Requires iOS | 18.5 | **8.0** |
| Devices | iPhone, iPad | **iPhone, iPad, iPod** |
| Age rating | 12+ | 12+ |
| Developer | [ECGsource LLC](https://appshunter.io/developer/377139096) | [RADIOLOGiQ, LLC](https://appshunter.io/developer/519524135) |

## What reviewers say

### CathSource

[App page](https://appshunter.io/ios/app/cathsource/id420847275)

A comprehensive medical reference focused on cardiac catheterization and angiography. It offers a searchable index of specialized topics, a database of videos of common and rare findings, and a collection of images including hemodynamic formulas and tables.

**Highlights:** Searchable index of cardiac catheterization topics, Database of coronary angiogram, ventriculogram, and aortogram videos, Image database with hemodynamic formulas and tables, Covers common and rare cardiovascular pathologies, Developed by practicing Interventional Cardiologists

**Features:** macOS Compatibility

**In-app purchases:** none


### Differential Diagnosis Guide

[App page](https://appshunter.io/ios/app/differential-diagnosis-guide/id523946690)

This app helps medical professionals and students review differential diagnoses for chest CT findings. It offers a powerful search tool and curated lists to explore diseases and their common imaging presentations, complete with over 100 CT images.

**Highlights:** Review differential diagnoses for chest CT findings, Discover common CT imaging presentations, Search hundreds of diseases and imaging findings, Browse differential diagnosis lists by organ system, Includes over 100 curated CT images, Voice recognition search

**Features:** macOS Compatibility

**In-app purchases:** none


## Frequently asked questions

### Is CathSource free?

CathSource is free to download, with no in-app purchases.

### Is Differential Diagnosis Guide free?

Differential Diagnosis Guide is free to download, with no in-app purchases.

### Which has better reviews, CathSource or Differential Diagnosis Guide?

Differential Diagnosis Guide is rated higher. CathSource averages 1.6 out of 5 from 23 ratings, while Differential Diagnosis Guide averages 4.5 from 22 ratings.

### Do CathSource or Differential Diagnosis Guide have ads?

Neither CathSource nor Differential Diagnosis Guide shows ads.

### Which is updated more often, CathSource or Differential Diagnosis Guide?

CathSource ships an update every 2 months, and Differential Diagnosis Guide every 4 months. Most recently, CathSource was updated on September 18, 2026 and Differential Diagnosis Guide on June 4, 2026.

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*Compared by [AppsHunter](https://appshunter.io/) from daily US App Store data. Review summaries are generated from verbatim App Store reviews.*